Numerous clinical studies have described the negative impact of radiotherapy-induced dermatitis on cancer patients during and after their 5-6 week course of radiotherapy. Virtually all patients develop at least a mild dermatitis, and for almost half it's a painful side effect lasting weeks. There can be scarring, limitations on more aggressive radiotherapy, and can result in patients quitting radiotherapy, with a significant effect upon tumor recurrence. There are no products on the market that prevent or treat this dermatitis. ProCertus, an early-stage biotech company, has developed a topically-applied small molecule drug for a product, DermX, that confers complete protection against the Grade 1->4 dermatitis seen in a rodent radiodermatitis model, a model that closely reflects the human experience. Based upon market analysis, ProCertus has concluded that a topical preventive for radiodermatitis would be well-received by cancer patients, and yield annual revenues in the range of $250 million. A DermX product would reduce radiotherapy-associated pain, could potentially enable more aggressive radiotherapy where dermatitis is dose-limiting, and could reduce the drop-out rate late in radiotherapy courses. Phase II funds will enable us to address the key, remaining issues in DermX scientific development, which are: i) ensure that topicallyapplied DermX does not affect external beam radiation killing of tumor cell xenografts in nude mice, ii) optimize a topical delivery vehicle that enables full radioprotection of skin stem cells while allowing insignificant levels of DermX active agent to enter systemic circulation, and iii) complete cGMP-certified batch synthesis of DermX that is required for studies prior to filing for its Investigational New Drug (IND) status. At the end of this Phase II project, ProCertus envisions a DermX product ready for clinical trials that: i) is a topical solution devoid of systemic side effects, ii) is applied 1-2 times in the 30 min before radiotherapy, and iii) is expected to prevent the Grade 1-4 dermatitis normally experienced by radiotherapy patients.